Ethernet over USB and UDEV

Trying to create a persistent configuration for such devices, that
utilize Ethernet over USB, I'm stuck.
Devices like these got no MAC address, apparently.
Is there anything that would uniquely identify such a device?
The name is pretty unique, but this is shared between all similar devices.
Any pointers how to solve this?.
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Esben Stien is b0ef at e s a
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